Hydrolyzable functional sylyl alkyl alkyl peroxides

ABSTRACT

Described herein are hydrolyzable functional silyl alkyl alkyl peroxides having the following general formula;

United States Patent [191 Joy [451 March 6, 1973 HYDROLYZABLE FUNCTIONAL2,692,868 10/1954 Berry et a1. ..260/89.5 A SYLYL ALKYL ALKYL PEROXIDES3,196,136 7/1965 Boutsicaris.... ..260/89.5 A 3,300,465 1 1967 B t l..260 89.5 A [75] inventor: John Richard Joy, Stevenson, Md. ayer e a I[73] Assignee: Union Carbide Corporation, New Primary Examiner-HarryWong York, Att0rneyPaul A. Rose et al.

[22] Filed: Dec. 8, 1971 57 ABSTRACT PP M11 ,164 Described herein arehydrolyzable functional silyl Related US. Application Data glllclial-alkyl peroxides having the following general for- [62] DlVlSlOn ofSer. No. 82,854, Oct. 21, I970. X3 n(Rn)SiR,OOR [52] US. Cl ..260/89.5A, 1 17/124, 260/465, wherein,

260/891, 260/935 S, 260/949 R, 260/448, X iS a hydrolyzable group, R ishydrogen or a 260/2 monovalent organic radical which is bonded to thesil- 51 Im. Cl. ..C08f 3/68, C08f 7/04 icon atom through a carbon tosilicon bond, is an 581 Field of Search ..260/93.5 s, 89.5 R, 89.5 A,alkenylene, cycloalkenylene, alkarylalkylene. or aral- 260/85 5 Fkylene, R is an alkyl or aralkyl, and n is 0 to 2 inclusive. Thesehydrolyzable silyl alkyl alkyl peroxides are [56] References Citeduseful as initiators for the polymerization of monomers having olefinicunsaturation and are also UNITED STATES PATENTS useful in formingsilicones.

3,297,669 1 1967 Harris et al ..260/85.5 F 3 Claims, No DrawingsI-IYDROLYZABLE FUNCTIONAL SYLYL ALKYL ALKYL PEROXIDES This is adivision, of application Ser. No. 82,854 filed Oct. 2, 1970.

This invention relates to silyl alkyl alkyl peroxides having at leastone hydrolyzable functional group, such as alkoxy, aryloxy, halide,amino, acyloxy and the like, bonded directly to the silicon atomthereof. This invention also relates to silicones, having siloxane unitswhich were formed through hydrolysis and condensation of saidhydrolyzable functional groups of the silyl alkyl alkyl peroxides.

It is known that it is difficult to initiate the polymerization ofmonomers having olefinic unsaturation while achieving a polymer havingterminal end groups capable of further reaction. The silyl alkyl alkylperoxides pursuant to this invention will readily thermally freeradicalize through the alkyl alkyl peroxy structure to permit suchpolymerization initiation. Upon such polymerization, the presence ofhydrolyzable functionality on the silicon atoms results in a chainterminated polymer having desired hydrolyzable functional end groupswhich are capable of forming bonds to polar substrates.

Certain acyl peroxides are known in the art and have been used asvulcanizing agents for rubbers and also as polymerization initiators.U.S. Pat. No. 2,963,501 discloses nonhydrolyzable organosilyl peroxidesformed by the reaction of the corresponding nonhydrolyzableorganosilicon alcohols with peroxides in the presence of sulfuric acid.This strong acid reaction would cause hydrolysis of a hydrolyzableorganosilicon alcohol and thus is incapable of providing hydrolyzablefunctional groups on the silicon atom.

U.S. Pat. No. 2,970,982 discloses different classes ofdiorganopolysiloxanes having a tertiary alkyl peroxy terminal groupwhich peroxy group is directly bonded to the terminal silicon atom ofthe polysiloxane chain. These materials are not silyl alkyl alkylperoxides as described herein.

This invention relates to silyl alkyl alkyl peroxides such as alkylalkyl peroxy silanes (alkylperoxyalkylsilanes) having the followinggeneral formula;

wherein X is any hydrolyzable functional radical such as alkoxy,aryloxy, halide, amino, acyloxy and the like; each R is one of hydrogenand a monovalent hydrocarbon radical such as alkyl, alkenyl, cycloalkyl,aralkyl, aryl and the like; R is an alkenylene, cycloalkenylene,alkaryalkylene or aralkylene radical; R" is an alkyl or aralkyl group;and n is an integer from 0 to 2 inclusive.

This invention also relates to the hydrolyzates and condensates of theafore-described hydrolyzable functional silyl alkyl alkyl peroxides,whereby siloxanes are formed. It is understood in the art, that when nequals 2, the resultant hydrolyzate and condensate is a disiloxane. Whenn equals 1, the hydrolyzate and condensate is an essentially linearsiloxane and when the silane is trifunctional, that is, when n is zero,the resultant hydroylzate and condensate contains siloxane crosslinkage.

The alkyl alkyl peroxy siloxanes pursuant to this invention can have anydegree of polymerization and may range from fluids to non-flowing gumsto resins wherein they possess the formula:

(ethylene)cumylene,

Ra (RO0RSi0 (RsSiO wherein a is 0, l or 2; b is 0, l, 2 or 3; x is anumber greater than 1; y is O or a number of at least 1; and each R,R'and R" is one of the radicals defined above therefor. Copolymerizationwith a broad range of siloxane is possible.

Illustrative of X are any hydrolyzable functional radicals such ashalide (such as bromide, chloride and fluoride), alkoxy (such asmethoxy, ethoxy, propoxy, dodecyloxy, isopropoxy and the like); aryloxy(such as phenoxy, naphthyloxy, triphenylmethyloxy, and the like);acyloxy (such as acetoxy, proprionoxy, and the like); amino; alkylaminoand arylamino (such as methyl amino, diethyl amino, phenyl amino, andthe like); hydroxy alkoxy (such as beta-hydroxyethoxy,gamma-hydroxypropoxy, and the like); chloroalkoxy (such asbeta-chloroethoxy, beta-chloro-propoxy, and the like); hydroxy; alkoxyalkoxy (such as beta-hydroxyethoxyethoxy,omega-hydroxy-(polyethyleneoxy); ethoxy;omega-hydroxy-(poly-l,2-propyleneoxy), and the like.

Illustrative of R is any monovalent hydrocarbon radical, such as alkylof from one to 18 carbon atoms (such as methyl, ethyl, n-pentyl,n-dodecyl, n-octadecyl, 2- ethyl-n-hexyl); cycloalkyl (such ascyclobutyl, cyclohexyl, and the like); aryl (such as phenyl, naphthyl,biphenyl, and the like); alkenyl (such as vinyl, allyl, methallyl,3-butenyl, and the like); alkaryl (such as tolyl, xylyl,2,4-diethyl-phenyl, 4- dodecylphenyl, and the like); aralkyl (such asphenylethyl); and the like.

Illustrative of R is a divalent hydrocarbon radical of from one to 18carbon atoms such as alkenylene (such as vinylene, propenylene,l-butenylene, Z-butenylene, 2-methyl-propenylene, and the like);cycloalkenylene (such as cyclopropenylene, 2,3-cyclobutenylene and thelike); aralkylene (such as phenylethylene, phenylpropylene,1-(4-methylphenyl) butylene, 3-ethylphenylethylene, naphthylethylene,and the like); alkarylalkylene (such as l-4-methylenephenylene, 4-l-methyi-3-5-methylene-phenylene, pcymenylene and the like IllustrativeR" is an alkyl group from one to 18 carbon atoms; ethyl, isopropyl,octadecyl, 2,2,4'trimethylpentyl; cycloalkyl groups included arecyclopropyl, cyclobutyl, cyclooctyl, l-methyl-2-ethylcyclohexyl, and thelike; or an aralkyl group of from one to 18 carbon atoms such asethylbenzyl, cumyl, triphenylmethyl, n-butylbenzyl, beta-phenylethyl,and the like.

The silyl alkyl alkyl peroxides pursuant to this invention can beprepared by the catalytic reaction of an alkyl or aralkyl hydroperoxidewith an organosilane containing at least one hydrolyzable functionalgroup and also having a hydrogen capable of abstraction as follows;

wherein the H of the organo silicon compound is bonded to an allyliccarbon atom of R when R is alkenylene or cycloalkenylene and H is bondedto a benzylic carbon atom when R is alkarylalkylene or aralkylene; X, R,R, R" and n are hereinbefore defined.

The catalyst in the above reaction is a metal salt, preferably a coppersalt, such as cuprous chloride or copper sulfate and is employed incombination with an organo-amide such as benzamide, acetamide, N-methylacetamide and the like. Benzamide is the preferred complexing agent whenused in conjunction with cuprous chloride.

The above reaction is carried out in the presence of a solvent such asaliphatic hydrocarbons, such as hexane or heptane, cycloaliphatichydrocarbons such as cyclopentane or cyclohexane, aromatic hydrocarbons,such as benzene, or toluene, and the like.

The operating temperature in the above reaction is not critical, but isadvantageously between 25 to 100C. and the reaction is carried out forperiods up to about 25 hours or more, if necessary.

Illustrative of the silanes suitable in the above reaction are;vinyltriethoxysilane, vinyl-tris (2-methoxyethoxysilane,vinyltriacetoxysilane,

phenyltrichlorosilane, phenyldimethylmonochlorosilane,phenyltriethoxysilane, phenylmonochloro-diethoxysilane,methylvinyldichlorosilane, naphthyltrimethoxysilane,butylbenzyldichlorosilane, cyclopropenyltriethoxysilane,vinylcumyloxysilane, 4-[2-(triethoxysilyl)ethyl] cyclohexene,4-[2-(trimethoxysilyl)ethyl] cumene, 4-[2-(dichloro-silyl)ethyl]cumeneand the like.

In the above reaction, HOOR" is an alkyl or aralkyl hydroperoxide.

Illustrative of such hydroperoxides are the following: methylhydroperoxide; ethyl hydroperoxide; propyl hydroperoxide; isopropylhydroperoxide; n-butyl hydroperoxide; sec-butyl hydroperoxide, t-butylhydroperoxide, t-amyl hydroperoxide; 1,1-diethylpropyl hydroperoxide;1,1 ,2-trimethylpropyl hydroperoxide; l-methylhexyl hydroperoxide;1,1,2,2- tetramethylpropyl hydroperoxide; cyclohexyl hydroperoxide;4-methylcyclohexyl hydroperoxide.

In the above reaction, HOR", is an alkyl or aralkyl alcohol which isremoved from the product reaction by water dissolution at elevatedtemperatures, approaching the solution boiling point, as shown in EX-AMPLES 1 and 2.

Silyl alkyl alkyl peroxides formed -butenyl(triethoxysilyl)isopropyl theabove reaction are for example; triethoxy-silyl propenyl cumyl peroxide,vinyl(- triethoxysilyl)propyl peroxide, vinyl(trichlorosilyl) cumylperoxide, 2-butenyl (triethoxysilyl)isopropyl peroxide,cyclopropenyl(dichlorosilyl) 4-methylcyclohexyl peroxide,phenyl(triethoxysilyl(cumyl peroxide, 4-[Z-(trimethoxysilyl)ethyl]cumylcumyl peroxide, 5-[2-(trimethoxysilyl)ethyl]-3-cyclohexenyl cumylperoxide, 4-[2-(trimethoxysilyl)ethyl]-3- cyclohexenyl cumyl peroxide,and the like.

The silyl alkyl alkyl peroxides, that is, the alkyl alkyl peroxy silanesof this invention, as stated previously, can be copolymerized with abroad range of siloxanes and cyclic siloxanes. This copolymerization iscarried out in the presence of an acid catalyst (for example, sulfuricacid).

The silyl alkyl alkyl peroxides of this invention can be used for any ofthe purposes for which peroxides are generally employed such asinitiators for the polymerization of olefms and as vulcanizing agentsfor rubbers. For examples the hydrolyzable functional silyl alkyl alkylperoxides can be used as initiators for the polymerization of monomershaving olefinic unsaturation. Illustrative of said operable monomersinclude the acrylic esters (such as methyl methacrylate); the alkenes,preferably those having omega unsaturation (such as propene andl-decene); the aryl alkenes (such as styrene, alpha-methylstyrene andthe like); the vinyl esters (such as vinyl acetate and the like); thevinyl benzyls; and vinyl biphenylene and the like, and the like. Morespecifically when a silyl alkyl alkyl peroxide is used as an initiatorfor the polymerization of styrene, the resulting polymer containshydrolyzable functional end groups. When the said resulting polymer isheatcured to a polar substrate, for example glass, a bond is formedwhich is highly resistant to water immersion.

The following examples are illustrative only and should not be construedin any way so as to limit the invention.

In the following examples, iodometric analyses to measure the activeoxygen content of the product silyl alkyl alkyl peroxides, to determinepurity, were performed according to the method of C]. Pederson, aspresented in 23 J.Org. Chem., 252(1958) and said analytical procedure isincorporated herein by reference.

EXAMPLE 1 A reaction charge was prepared by mixing 7.6 grams of cumenehydroperoxide (83 percent purity), 26.5 grams of4-[Z-(trimethoxy-silyl)ethyl]cumene(pr epared by reacting4-isopropylstyrene and trimethoxysilane with chloroplatinic acidcatalyst), 1.0 grams of benzamide, 0.20 parts of copper (I) chloride and44 grams of benzene. This charge was heated at 89C. for 1 hours, duringwhich water formed by the chemical reaction was removed employing aDean-Stark trap. Ninety-one percent of the cumene hydroperoxide wasconsumed by the reactionfThe charge was then cooled and filtered. Thebenzene was removed in vacuo of at about mm Hg for 60 minutes at 25C.About grams of hexane was added to the product mixture and the mixturewas filtered through No. 3 paper to remove precipitate benzamide. Thehexane was removed in vacuo of at 100 mm Hg for 60 minutes at ambienttemperature. Unreacted cumene hydroperoxide and byproduct cumyl alcoholwere removed by distillation using a water bath at a maximum temperatureof 93C. The residue was centrifuged for 1 hour at 10,000 rpm. in aServall SS-3 centrifuge having a 88-34 rotor. The product,4-[2(-trimethoxysilyl)ethyl]cumyl cumyl peroxide, was obtained as 26.1grams 39.3 percent purity as determined by active oxygen analysis by HIcleavage.

EXAMPLE 2 A reaction was prepared by mixing 7.6 grams of cumenehydroperoxide (83% purity), 23.10 grams of 4-[2(triethoxysilyl)ethyl]cyclohexene(prepared by reacting4-vinylcyclohexene and trimethoxysilane with chloroplatinic acidcatalyst), 0.100 grams of copper (I) chloride, 0.500 grams of benzamideand 44 grams of benzene. The charge was refluxed 89C. for 5 hours,during which water formed by the chemical reaction was removed via aDean-Stark trap. Most of the cumene hydroperoxide (viz. 90.6 percent)was consumed by the reaction. The charge was then cooled and filteredthrough a No. 3 paper. Benzene was removed in vacuo of 100 mm Hg for 60minutes at ambient temperature. By-product and unreacted startingmaterial were both removed by vacuum distillation at 0.04 mm Hg, using awater bath as heat source to a maximum temperature of 89C. The distilledresidue was centrifuged for 30 minutes at 10,000 rpm. in a Servall SS-3centrifuge using a 85-34 rotor. The product, was 8.1 grams 5-[Z-(trimethoxysilyl)ethyl]-3-cyclohexenyl cumyl peroxide and the isomer4-[2-(trimethoxysilyl)ethyl]-3-cyclohexenyl cumyl peroxide. Activeoxygen analysis by HL cleavage indicated 54.8 percent purity.

EXAMPLE 3 A test tube was sparged with argon and charged with 10.5 partsof methyl methacrylate (distilled, boiling point of 53C. at 133 mm Hg)and 0.1 part of 4-[2- (trimethoxysilyl)ethyl]cumyl cumyl peroxide. Thetube was heated in an oil bath starting at 100C. and approaching 250C.The charge became viscous within l5 minutes (200C.) and solid after 45minutes (250C.).

What is claimed is:

1. In the method for olefin polymerization of at least a monomer havingpolymerizable olefinic unsaturation, the improvement wherein ahydrolyzable function silyl alkyl alkyl peroxide having the followinggeneral formula;

wherein, X is a hydrolyzable group, R is hydrogen or a monovalenthydrocarbon radical which is bonded to the silicon atom through a carbonto silicon bond, R is an alkenylene, cycloalkenylene, alkaryl alkylene,or aralkylene, R" is an alkyl or aralkyl, and n is 0 to 2 inclusive, isused as a polymerization initiator.

2. Claim 1, wherein said monomer is styrene.

3. Claim 1, wherein said monomer is methyl methacrylate.

1. In the method for olefin polymerization of at least a monomer havingpolymerizable olefinic unsaturation, the improvement wherein ahydrolyzable function silyl alkyl alkyl peroxide having the followinggeneral formula; X3 n(Rn)SiR''OOR'''' wherein, X is a hydrolyzablegroup, R is hydrogen or a monovalent hydrocarbon radical which is bondedto the silicon atom through a carbon to silicon bond, R'' is analkenylene, cycloalkenylene, alkaryl alkylene, or aralkylene, R'''' isan alkyl or aralkyl, and n is 0 to 2 inclusive, is used as apolymerization initiator.
 2. Claim 1, wherein said monomer is styrene.